This invention relates generally to the wheel balancing industry, and more specifically, to a vehicle wheel balancer adapted for determining the location and degree of imbalance of a vehicle wheel prior to mounting the wheel on a vehicle. The invention utilizes an improved centering sleeve which functions to center the wheel about a rotational axis defined by the balancer shaft. In order to obtain accurate balancing results, the wheel must remain precisely centered during operation of the wheel balancer. Upon rotation of the wheel, conventional electronic sensors and circuitry acquire data indicating the appropriate placement of balancing weights on the wheel. Proper wheel balancing is essential to achieving a smooth, vibration-free drive.
Centering sleeves, also known as xe2x80x9cconesxe2x80x9d, have been used in the wheel balancing industry for many years. In order to accommodate wheels for passenger cars, light trucks, SUVs, and vans, centering sleeves must cover a variety of wheel hole sizes ranging generally from 42 mm to 133 mm in diameter. In the past, it was preferable to have only a few different sleeves, generally 3-5, each of which fit a range of several different wheel hole sizes so that an operator could readily determine which sleeve to use for the particular wheel to be balanced. To meet this need, relatively high-angle conical sleeves were developed. While these sleeves could accommodate many different wheel sizes, it was discovered that because of their relatively high angle, wheel centering was less precise causing the balancing results to be less accurate.
In the industry today, it is well accepted that a low angle sleeve provides better wheel centering and more accurate results. Indeed, a very low angle sleeve, one which is nearly cylindrical, will generally give the most accurate and repeatable balancing results.
Nevertheless, the low-angle sleeves have drawbacks and limitations. Since the angle is low, an operator must have access to several different sleevesxe2x80x94generally, 25 or morexe2x80x94in order to cover the entire standard range of wheel hole sizes. Proper selection of a centering sleeve for a given wheel is generally achieved through trial and error, and/or time-consuming measurements. In some cases, an operator simply uses the wrong sleeve size to balance the wheel. Moreover, because of the low angle of these sleeves, the wheel fits more tightly on the sleeve. Standard xe2x80x9cwing nutxe2x80x9d tighteners exert a force of as much as 3 to 3.5 tons of static pressure to torque the wheel onto the balancer. When the wheel is removed after operation of the balancer, the centering sleeve generally sticks in the wheel hole creating a frictional attachment which is often difficult to release without damaging the sleeve and/or wheel. Despite these problems, the increased importance of proper wheel balancing in today""s vehicles is driving the industry toward the use of low-angle centering sleeves.
The present invention addresses a need in the industry for a vehicle wheel balancer using a low-angle sleeve which produces accurate balancing results in a timely and efficient manner. Unlike other low-angle sleeves, the present sleeve does not lodge in the wheel hole as the wheel is removed from the balancer. Moreover, by utilizing a specially-designed electronic or mechanical tool for matching the proper centering sleeve to a given wheel, the guess-work otherwise required when selecting a low-angle sleeve is eliminated. Alternatively, the sleeves may be color-coded, numbered, or marked with other suitable indicia used to match the appropriate sleeve to the given wheel based on information provided on a selection chart.
Therefore, it is an object of the invention to provide an improved centering sleeve for a vehicle wheel balancer. The term xe2x80x9ccentering sleevexe2x80x9d as used herein is broadly defined as any cylindrical or conical device designed for centering the vehicle wheel relative to a rotational axis defined by the balancer shaft.
It is another object of the invention to provide a centering sleeve which has a low angle and will not lodge within the center hole of the vehicle wheel when the wheel is removed from the balancer.
It is another object of the invention to provide a centering sleeve which releasably locks to the wheel balancer, and is conveniently interchanged with similar sleeves of different sizes in order to accommodate vehicle wheels having center holes ranging from 42 mm to 133 mm in diameter.
It is another object of the invention to provide a measuring device which measures the center hole of the vehicle wheel, and indicates by (number, letter, color, etc.) the appropriate sleeve required for use on the wheel balancer in order to obtain accurate balancing results.
It is another object of the invention to provide an improved vehicle wheel balancer especially adapted for balancing steel and alloy wheels used on passenger vehicles, SUVs, vans, and light trucks.
It is another object of the invention to provide an improved method for balancing a vehicle wheel.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a vehicle wheel balancer for obtaining data relative to the imbalance of a vehicle wheel. The wheel balancer includes a centering shaft having a free end adapted for extending through a center hole of the wheel, and a proximal end opposite the free end. Means are provided for rotating the centering shaft. A locating hub is carried on the shaft, and is adapted for engaging a first side of the wheel to locate the wheel on the balancer. A centering sleeve is carried on the shaft adjacent the locating hub, and is adapted for extending through the center hole of the wheel to center the wheel relative to the shaft. Means are provided for locking the centering sleeve to the wheel balancer, such that the centering sleeve remains secured to the wheel balancer upon removal of the wheel from the shaft. A mounting member is carried on the shaft, and is adapted for engaging a second side of the wheel. The wheel is sandwiched between the mounting member and the locating hub such that the mounting member, locating hub, and centering sleeve cooperate to secure the wheel in a centered position relative to the shaft during wheel-balancing rotation of the wheel.
Preferably, the means for rotating the centering shaft includes an electric motor and drive shaft mounted within a journal bearing. The drive shaft and centering shaft may be integrally formed together, or formed separately and operatively coupled. Alternatively, the centering shaft may be rotated manually by hand-rotating the wheel. The means for rotating the centering shaft in this embodiment includes the journal bearing.
Preferably, the mounting member is a mounting flange plate. Alternatively, the mounting member may be a pressure cup and/or wingnut.
According to another preferred embodiment of the invention, the locating hub has an annular face plate adapted for engaging the wheel, and an integrally-formed cup defining an internal cavity for receiving a portion of the centering sleeve.
According to another preferred embodiment of the invention, a spring is positioned within the cavity of the locating hub, and is adapted for urging the centering sleeve into the center hole of the wheel.
According to another preferred embodiment of the invention, a floating spring cover is movable within the cavity of the locating hub and resides between the spring and centering sleeve.
According to another preferred embodiment of the invention, the means for locking the centering sleeve to the wheel balancer includes a locking bolt extending outwardly from the centering sleeve towards the floating spring cover. The floating spring cover defines an opening for receiving and holding a free end of the locking bolt to secure the centering sleeve to the wheel balancer.
According to another preferred embodiment of the invention, the locking bolt has an enlarged head. The opening in the floating spring cover defines an enlarged portion adapted for receiving the head of the bolt and a narrow portion communicating with the enlarged portion. After inserting the bolt head through the enlarged portion of the opening, the centering sleeve is rotated to locate the bolt head along the narrow portion of the opening such that the bolt head engages the floating spring cover to lock the centering sleeve to the wheel balancer.
According to another preferred embodiment of the invention, the means for locking the centering sleeve to the wheel balancer includes one or more locking clips, mating screw threads, interfering shoulders, projecting fingers, and the like.
According to another preferred embodiment of the invention, the free end of the centering shaft has an external screw thread.
According to another preferred embodiment of the invention, a wing nut is applied to the free end of the centering shaft. The wing nut has a complementary internal screw thread mating with the external thread of the centering shaft to releasably secure the wheel between the locating hub and mounting member.
In another embodiment, the invention is a wheel centering assembly for a vehicle wheel balancer adapted for obtaining data relative to the imbalance of a vehicle wheel. The wheel centering assembly includes a centering shaft having a free end adapted for extending through a center hole of the wheel, and a proximal end. A locating hub is carried on the centering shaft, and is adapted for engaging a first side of the wheel to locate the wheel on the balancer. A centering sleeve is carried on the shaft adjacent the locating hub, and is adapted for extending through the center hole of the wheel to center the wheel relative to the shaft. Means are provided for locking the centering sleeve to the wheel balancer, such that the centering sleeve remains secured to the wheel balancer upon removal of the wheel from the shaft. A mounting member is carried on the shaft, and is adapted for engaging a second side of the wheel. The wheel is sandwiched between the mounting member and the locating hub. The mounting member, locating hub, and centering sleeve cooperate to secure the wheel in a centered position relative to the shaft during wheel-balancing rotation of the wheel.
In yet another embodiment, the invention is a centering sleeve adapted for extending through a center hole of a vehicle wheel mounted on a vehicle wheel balancer to center the wheel relative to a rotatable balancer shaft. The centering sleeve includes means for locking the sleeve to the wheel balancer, such that the sleeve remains secured to the wheel balancer upon removal of the wheel from the balancer shaft.
According to another preferred embodiment of the invention, the centering sleeve includes an enlarged base adapted for engaging a floating spring cover movable within a cavity defined by a locating hub of the wheel balancer.
According to another preferred embodiment of the invention, the means for locking the centering sleeve to the wheel balancer includes a locking bolt extending outwardly from the base. The locking bolt is adapted for being inserted and held within an opening formed with the floating spring cover to secure the centering sleeve to the wheel balancer.
In yet another embodiment, the invention is a method for balancing a vehicle wheel. The method includes the steps of mounting the wheel on a vehicle wheel balancer including a rotatable shaft. The wheel is centered relative to the shaft using a centering sleeve extending into a center hole of the wheel. With the wheel mounted and centered, the shaft is rotated to obtain data relative to the imbalance of the wheel. After the data is obtained, the wheel is removed from the wheel balancer while simultaneously dislodging the centering sleeve from the wheel hole.